Identification and quantification of phenolic acids and anthocyanins as antioxidants in bran,embryo and endosperm of white,red and black rice kernels (Oryza sativa L.)

Whole rice grain comprising endosperm, embryo (or germ), and bran has potential beneficial health effects in addition to provision of nutrients. The distribution of phenolic acids and anthocyanins in endosperm, embryo, and bran of white, red, and black rice grains was investigated in this study. The total phenolic content (TPC) was highest in the bran, averaging 7.35 mg GAE/g and contributing 60%, 86% and 84% of phenolics in white, red and black rice. The average TPC of the embryo and endosperm were 2.79 and 0.11 mg GAE/g accounting for 17% and 23%, 4% and 10% and 7% and 9% in white, red and black rice, respectively. The antioxidant capacity determined using DPPH and ORAC displayed a trend similar to TPC. Free/conjugated phenolic acids in white, red and black rice bran accounted for 41%, 65% and 85% of total acids. Bound phenolic acids in rice bran accounted for 90% of total acids in whole grain. Cis-p-coumaric was detected in bound form in bran while cis-sinapic acid was detected in the free/conjugated form in embryo and bran. Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were identified mainly in black rice bran as the total anthocyanins. Cyanindin-3-O-rutinoside was also detected in black rice bran.     

The Content of Phenolic Compounds and Radical Scavenging Activity Varies with Carrot Origin and Root Color

The contents of phenolic compounds and radical scavenging activities were assessed in a carrot collection comprising 35 cultivars, landraces and breeding populations. The accessions originated from various world regions and they represented Eastern and Western carrot gene pools. In two-year field trial carrot roots of orange, red, yellow, white and purple color were cultivated, freeze-dried and analyzed for phenolic content by Folin-Ciocalteu assay and UV/Vis assay. Radical scavenging activity in the extracts was determined with a stable DPPH radical. Carrots developing purple roots possessed on average 9 times more phenolics than roots of other colors. Furthermore, they were rich in anthocyanins that caused very high antiradical activity. Red carrots showed higher antioxidant activity than orange, yellow and white carrots and in the season of lower rainfall they accumulated higher amounts of phenolic compounds. Carrots of Asian origin belonging to Eastern gene pool were more often purple or red and richer in phenolics and had higher antiradical activity than those from the Western gene pool with mainly orange roots.     

Total phenolics,flavonoids, antioxidant capacity in rice grain and their relations to grain color,size and weight

Total phenolics, flavonoid contents and antioxidant capacity from a wide collection of rice germplasm were measured, and their relations to grain color, grain size and 100-grain weight were investigated. Highly significant genotypic differences were observed in total phenolics, flavonoid contents and 2,2-azino-bis-(3-ehylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation antioxidant capacity. They displayed an increasing order in the white rice, red rice and black rice, yet several white rice had higher phenolics and flavonoids contents than the red rice. Significant positive pair-wise correlations were found among the phenolics, flavonoid contents and antioxidant capacity, and the coefficient between the phenolic contents and antioxidant capacity was extremely high (r = 0.96). Among all rice accessions, the grain color parameters had negative correlations with the phenolics, flavonoid contents and antioxidant capacity (p < 0.001). The negative correlation between a* and antioxidant capacity, and the positive correlation between H° and antioxidant capacity were consistent within the respective white rice and red rice groups. Flavonoid contents had positive correlation with grain length and length to width ratio, and had negative correlation with the 100-grain weight among all rice accessions. It was also found that 100-grain weight still had negative correlations with phenolics, flavonoid contents and antioxidant capacity within the white rice genotypes. These relationships may serve as indexes to indirectly select breeding lines high in the phenolics, flavonoids and antioxidant capacity. Principal component analysis including the information for phenolics, flavonoids, antioxidant capacity, grain color parameters, grain size and 100-grain weight extracted five principal components that explained 83.7% of the total variances. The results of this study may provide new opportunities for rice breeders and eventually commercial rice growers to promote the production of rice with enhanced nutritional quality.     

Antioxidants in potato

The content of compounds in potato that may act as antioxidants in the human diet is not widely appreciated. Carotenoids are present in the flesh of all potatoes. The contents mentioned in the literature range from 50 to 100 μg per 100 g fresh weight (FW) in white-fleshed varieties to 2000 μg per 100 g FW in deeply yellow to orange-fleshed cultivars. The carotenoids in potato are primarily lutein, zexanthin, and violaxanthin, all of which are xanthophylls. There is just a trace of either alpha or beta-carotene, meaning that potato is not a source of pro-vitamin A carotenes. In potatoes with total carotenoids ranging from 35 to 795 μg per 100 g FW, the lipophilic extract of potato flesh presented oxygen radical absorbance capacity (ORAC) values ranging from 4.6 to 15.3 nmoles α-tocopherol equivalents per 100 g FW. Potatoes contain phenolic compounds and the predominant one is chlorogenic acid, which constitutes about 80% of the total phenolic acids. Up to 30 μg per 100 g FW of flavonoids are present in the flesh of white-fleshed potatoes with roughly twice the amount present in red and purple-fleshed potatoes. The predominant flavonoids are catechin and epicatechin. Red and purple potatoes derive their color from anthocyanins. The skin alone may be pigmented, or the flesh may be partially or entirely pigmented. Whole unpeeled with complete pigmentation in the flesh may have up to 40 mg per 100 g FW of total anthocyanins. Red-fleshed potatoes have acylated glucosides of pelargonidin while purple potatoes have, in addition, acylated glucosides of malvidin, petunidin, peonidin, and delphinidin. The hydrophilic antioxidant activity of solidly pigmented red or purple potatoes is comparable to brussels sprouts or spinach. In red and purple potatoes with solidly pigmented flesh with levels of total anthocyanin ranging from 9 to 38 mg per 100 g FW, ORAC ranged from 7.6 and 14.2 umole per g FW of Trolox equivalents. Potato contains on average 20 mg per 100 g FW of vitamin C, which may account for up to 13 % of the total antioxidant capacity. Potatoes should be considered vegetables that may have high antioxidant capacity depending on the flesh composition.     

Hydrothermal and biotechnological treatments on nutraceutical content and antioxidant activity of rice bran

The effect of processing such as steaming, germination and parboiling on nutraceuticals and in vitro bioactive properties of rice bran from three different rice varieties namely Jyothi (pigmented), IR64 and Sona masuri (non-pigmented) were investigated. Within the varieties envisaged, pigmented Jyothi variety contained higher levels of vitamin E, soluble, bound and total polyphenol, flavanoids, free radical scavenging activity and total antioxidant activity. Direct steam exposure of bran resulted in an increase in, ether extractives and oryzanol, as well as retention of all the vitamin E components, bound polyphenols, flavonoids and decrease in soluble and total polyphenol content, free radical scavenging activity and total antioxidant activity compared to native. Parboiling as well as germination of paddy resulted in an increase, in the content of ether extractives and oryzanol, whereas other bioactive properties decreased compared to native. Hence it may be concluded that bioactive components and antioxidant properties were significantly higher in Jyothi bran compared to the other two paddy brans, and processing leads to changes in bioactive properties with maximum retention of bioactive components in the steamed bran.     

Effects of microfluidization on antioxidant properties of wheat bran

Phenolic compounds present in native wheat bran are majorly bound to polysaccharides and entrapped in the fibre matrix. Recently, it was demonstrated that the microfluidization process could significantly improve physicochemical properties of wheat bran due to particle size reduction and microstructure modification. The current study provides further evidence that the process also significantly increased the contents of surface-reactive, alkaline and acid hydrolysable phenolics by 280%, 60% and 20%, respectively, after a total of 8 passes through the IC₂₀₀ and IC₈₇ chambers. Accordingly, the associated antioxidant capacity increased with increase in the extent of the treatment. However, there was a decrease in solvent extractable phenolic contents due to their dispersion in water and loss during the treatment. It is also worth noting that the residues after alkaline and acid hydrolysis still contained a high content of surface-reactive phenolics, which might indicate a significant underestimation of the total phenolic content and antioxidant capacity of wheat bran when using the conventional method based on solvent extraction and alkaline and/or acid hydrolysis.     

不同产地紫米营养成分比较及其相关性分析

为评价不同品种紫米淀粉、脂肪、花青素、多酚、氨基酸和矿质元素间的差异,探究不同营养成分之间的关系,选取云南墨江（MJ）、湖南新化（HN）、贵州黎平（GZ）和陕西汉中（SX）4个产地的紫米,并与红米（R）、黑米（B）进行比较。结果显示,不同产地紫米成分含量存在差异,具有不同营养特征。HN紫米的淀粉含量最低（68.13%）,脂肪（2.38%）、矿质元素Fe、K、Mg、Mn、Na、P、Zn含量最高,其中Mn（80.37 mg/kg）、Na（10.75 mg/kg）元素显著高于其他产地;MJ和SX紫米花青素（533.03 mg/kg,412.54 mg/kg）、多酚（340.55 mg/100 g,387.91 mg/100 g）含量显著高于其他产地,而GZ紫米花青素（156.55 mg/kg）和多酚（239.23 mg/100 g）显著低于其他产地紫米。SX紫米氨基酸总量（74.37 g/kg）与必需氨基酸（total essential amino acids,ΣEAA,26.09 g/kg）含量最高,与其他紫米差异不显著。紫米成分间相关性分析显示,花青素与多酚呈极显著正相关（0.625）,二者分别与Ca呈显著负相关（-0.571,-0.549）。Asp、Gly与Fe、Ca呈显著正相关,大部分元素间呈显著正相关。不同有色稻米间,红米淀粉（74.73%）含量最高,花青素（9.05 mg/kg）、氨基酸总量（55.94 g/kg）、ΣEAA（19.78 g/kg）、Fe（6.51 mg/kg）、Mg（609.41 mg/kg）、P（1746.72 mg/kg）元素含量最低,与紫米和黑米差异显著（P<0.05）。黑米花青素（533.03 mg/kg）、多酚（453.53 mg/100 g）含量显著高于（P<0.05）其他有色稻;黑米和紫米氨基酸含量差异不显著（P>0.05）,但显著高于（P<0.05）红米。有色稻ΣEAA与非必需氨基酸总量（total non-essential amino acid,ΣNEA）比例在0.54左右。主成分分析将3种有色稻分为红米、紫黑米两组,前3个主成分可以解释总方差的91%。第一主成分（PC1）贡献率为67.5%,代表矿质元素,说明产地是有色稻米成分组成差异的主要原因。第二主成分（PC2）占总方差的18.2%,主要为总花青素含量、氨基酸等。     

Phase II-Inducing,Polyphenols Content and Antioxidant Capacity of Corn (<Emphasis Type="Italic">Zea mays</Emphasis> L.) from Phenotypes of White,Blue, Red and Purple Colors Processed into Masa and Tortillas

White, blue, red and purple corns (Zea mays L.) were lime-cooked to obtain masa for tortillas. The total phenolics and anthocyanins content, antioxidant activity expressed as total reducing power (TRP), peroxyl radical bleaching (PRAC), total antioxidant activity (TAA) and quinone reductase (QR) induction in the murine hepatoma (Hepa 1 c1c7 cell line) as a biological marker for phase II detoxification enzymes were investigated. Among the extracts prepared from raw corn varieties the highest concentration of total phenolics, anthocyanins, antioxidant index and induction of QR-inducing activity were found in the Veracruz 42 (Ver 42) genotype. The nixtamalization process (masa) reduced total phenolics, anthocyanins and antioxidant activities and the ability for QR induction when was compared to raw grain. Processing masa into tortillas also negatively affected total phenolics, anthocyanin concentration, antioxidant activities, and QR induction in the colored corn varieties. The blue variety and its corresponding masa and tortillas did not induce QR. Ver 42 genotype and their products (masa and tortilla) showed the greatest antioxidant activity and capacity to induce QR     

Color and Antioxidant Characteristics of Some Fresh Fig (Ficus carica L.) Genotypes from Northeastern Turkey

Fruit skin color, total phenolics, total anthocyanins, soluble solids content, titratable acidity and total antioxidant capacity in fresh fruits of a number of local and well-known fig (Ficus carica L.) genotypes and cultivars grown in northeastern Turkey were determined. TEAC (Trolox equivalent antioxidant capacity) and FRAP (ferric reducing antioxidant power) assays were used to determine total antioxidant capacity. Fruit skin color of genotypes were found to be very diverse, i.e., light green, light purple, purple, dark purple and black. The content of total phenolics, soluble solids content (SSC) and titratable acidity greatly varied in the range from 24 to 237?mg of gallic acid equivalent per 100?g fresh weight, 18.60 to 26.30?% and 0.16 to 0.47?% in local genotypes and studied cultivars. In general, total antioxidant capacities determined by two methods expressed higher values in the local fig genotypes compared with the cultivars. The results suggested that genotype is the main factor that determines difference in the composition of bioactive compounds in figs and provide information on putative health benefits locally grown genotypes.     

Functional suitability of commercially milled rice bran in India for use in different food products

The effect of blending of commercially available full fat and defatted rice brans in India from modern multistage rice mills with parboiling/stabilizing facilities in different food products in comparison to those obtained from laboratory milling of rice is reported. Bread volume and cookie spread decreased but muffin volume increased with the addition of different types of bran to wheat flour, however, the cookie spread factor was not affected by addition of full fat rice bran. The yields of the extrudate were increased by the blending of full fat rice bran but were decreased by the addition of defatted rice bran. Rice brans could be added to different food products to the extent of 5–10%. However, the full fat rice bran could not be used for production of extruded snack food.     

Distributions of phenolic compounds,yellow pigments and oxidative enzymes in wheat grains and their relation to antioxidant capacity of bran and debranned flour

In this study, the distribution of phenolic compounds and yellow pigments in wheat grains and their relation to the total antioxidant capacity of bran and debranned flour was investigated. Yellow pigments, the activity of lipoxygenase (LOX) and peroxidase (POX) enzymes were also determined. The bran fraction was found to contain significantly higher concentrations of phenolic acids, flavonoids and yellow pigments. The LOX activity was concentrated in endosperm and embryo, while the POX activity mostly concentrated in the bran fraction. The results suggest that the bran fraction of wheat would potentially provide naturally occurring antioxidants. From the health benefit point of view, a small level of bran incorporation to bread can be recommended to increase dietary fibre and phytonutrients in the diet.     

Distributions of phenolic compounds,yellow pigments and oxidative enzymes in wheat grains and their relation to antioxidant capacity of bran and debranned flour

In this study, the distribution of phenolic compounds and yellow pigments in wheat grains and their relation to the total antioxidant capacity of bran and debranned flour was investigated. Yellow pigments, the activity of lipoxygenase (LOX) and peroxidase (POX) enzymes were also determined. The bran fraction was found to contain significantly higher concentrations of phenolic acids, flavonoids and yellow pigments. The LOX activity was concentrated in endosperm and embryo, while the POX activity mostly concentrated in the bran fraction. The results suggest that the bran fraction of wheat would potentially provide naturally occurring antioxidants. From the health benefit point of view, a small level of bran incorporation to bread can be recommended to increase dietary fibre and phytonutrients in the diet.     

Phytochemicals and Antioxidant Capacity of Tortillas Obtained after Lime-Cooking Extrusion Process of Whole Pigmented Mexican Maize

The lime-cooking extrusion represents an alternative technology for manufacturing pre-gelatinized flours for tortillas with the advantages of saving energy and generation of null effluents. The phytochemical profiles (total phenolics, anthocyanins) and antioxidant activity of four different types of whole pigmented Mexican maize [white (WM), yellow (YM), red (RM), blue maize (BM)] processed into tortillas were studied. The lime-cooking extrusion process caused a significant decrease (p?相似文献   

Protein utilization of pigmented and nonpigmented brown and milled rices by rats

The protein of pigmented brown rices had similar lysine content as that of nonpigmented brown rices, but it was less digestible in rats. Because of higher biological value, only the purple rice, but not red rice, had lower net protein utilization than two nonpigmented rices. Milling, which removed bran-polish and reduced pigment and phenolic content, improved the digestibility of the pigmented rices.     

Evaluation of the Total Antioxidant Capacity,Polyphenol Contents and Starch Hydrolase Inhibitory Activity of Ten Edible Plants in an In vitro Model of Digestion

The total phenolics contents, total antioxidant capacity (TAC) and starch hydrolase inhibitory activity of the aqueous extracts of 10 edible plants and the stability of these parameters after the gastric and duodenal digestion in an in vitro model was investigated. The TAC was evaluated using the oxygen radical absorbance capacity (ORAC) assay, ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH?) and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS?+) radical scavenging assays. Characterization and quantification of five polyphenol compounds which were previously identified to be present in all the selected plants were carried out. None of the extracts showed a decrease in the total phenolics content or the ORAC and FRAP values following digestion. None of the quantified phenolic compounds had decreased during any of the digestion phases – an observation which was deemed as beneficial in terms of therapeutic properties. Overall, the parameters analyzed were relatively stable throughout the digestive process in all the extracts.

     

Valorization of rice by-products: Protein-phenolic based fractions with bioactive potential

Rice bran (RB) is an important by-product from the rice production with a high valorization potential. The aim of the present work was to explore this potential by considering combined protein and phenolic fractions and enzymatic hydrolysis. The influence of different protocols in the recovery/fractioning of protein were evaluated, including defatting procedures, in rice brans from two very different locations: Portugal and Colombia. The different protein fractions achieved were characterized. Proteins were further hydrolyzed using trypsin and their hydrolysates were characterized in terms of degree of hydrolysis and peptide size. Moreover, the total phenolic content (TPC) and phenolic compounds’ profile on extracted fractions and hydrolysates of RB from Portugal and Colombia were determined. The functional potential was assessed in terms of antioxidant and antihypertensive activities. Though the protein concentrates had already significant potential bioactivities, protein hydrolysates showed that the TPC, antioxidant and antihypertensive activities significantly increased with the digestion by trypsin. Hydrolysates of RB from Portugal presented a higher antioxidant and hypertensive activities in comparison with hydrolysates of RB from Colombia, moreover it presented a higher content of TPC. This study indicated that the exploitation potential of rice bran can be increased with simple fractioning procedures, that combined protein/phenolic fractions are important to deliver functionality and that hydrolysis can be a relevant tool to release that functionality. Furthermore, regional differences in rice bran composition are also important factors to consider. Overall, this knowledge can be used to increase the industrial potential of valorization for this by-product.     

Bioactive Compounds and Antioxidant Capacity of Strawberry Jams

Strawberries represent the main source of ellagic acid derivatives in the Brazilian diet. They are also good sources of flavonoids, mainly anthocyanins, and phenolic acids, to which many beneficial effects have been attributed. However, as the fruit is not available all the year, the objective of this work was to determine whether the jams could also represent a good source of bioactive compounds. In the current study, five different commercially available strawberry jams were characterized in relation to flavonoids, total phenolics, free and total ellagic acid contents, and antioxidant capacity. Anthocyanins were detected only in two jams at very low content. Kaempferol glycosides were the main flavonoids present (from 0.38 to 1.05 mg/100 g fresh weight, FW), while quercetin glycosides were present in the range 0.14–1.20 mg/100 g FW. Free and total ellagic acid content ranged from 0.4 to 2.9 mg/100 g FW, and from 17.0 to 29.5 mg/100 g FW, respectively. Total phenolics varied from 58 to 136 mg/100 g FW, and the antioxidant capacity from 0.55 to 0.76 μmol BHT (Butylhydroxytoluene) equivalents/g FW. Overall, results indicated that jams can also represent a good source of antioxidant compounds, although compared to the fruit important losses seem to occur.     

Antioxidant properties of wheat and rye bran extracts obtained by pressurized liquid extraction with different solvents

Rye and wheat brans are valuable sources of bioactive compounds, which could be used for the development and commercialization of high added value functional ingredients such as dietary antioxidants. The aim of this study was to evaluate antioxidant potential of rye and wheat bran using different polarity solvents. Cereal brans were ground to four different particle size fractions and extracted at 10.3 MPa pressure and 80 °C temperature by consecutive application of hexane, acetone and methanol:water (80:20%). The highest extract yield was obtained from rye bran using methanol-water; particle size in most cases had a significant effect. Antioxidant potential of extracts was assessed by ABTS^+•, DPPH^• scavenging, ORAC and total phenols content (TPC) assays. Extraction solvent had a major influence on TPC and antioxidant activity of the extracts. The most active extracts were obtained using methanol:water; rye bran extracts, in general, were stronger antioxidants than wheat bran extracts. For the majority of assays, reduction of particle size resulted in higher antioxidant activity values. However, ABTS^+• scavenging was found to decrease by decreasing particle size of rye bran used for extraction.     

Antioxidant activity of small grain cereals caused by phenolics and lipid soluble antioxidants

In this study, the content of soluble, free forms of phenolic compounds (total phenolics, flavonoids, PVPP (polyvinylpolypyrrolidone) bound phenolics, proanthocyanidins and phenolic acids), as well as the content of carotenoids and tocopherols, were determined in whole grains of bread and durum wheat, rye, hull-less barley and hull-less oat, each represented with four genotypes. Antioxidant activity was evaluated as radical scavenging activity with DPPH (2,2-diphenyl-1-picrylhydrazyl) reagent, as well as by hydrogen transfer reaction (reduction power) based on the reduction of Fe³⁺. Generally, a considerable variation in antioxidant activities and phytochemical contents was observed between the cereals. Remarkably higher DPPH radical scavenging ability and reducing power were detected in hull-less barley, followed by rye and hull-less oat and durum and bread wheat, indicating that small grain species have different major antioxidants with different properties. Hull-less barley had the highest content of total free phenols, flavonoids, PVPP bound phenolics and contained flavan-3-ols, not found in other species. Hull-less oat had the highest content of tocopherols, very high content of yellow pigments and PVPP bound phenolics. Ferulic acid was the major free phenolic acid in small grain cereals tested. The relationship between the content of soluble phenols, as well as reducing power and DPPH^• scavenging activity are also considered.     

Effect of various heat treatments on rancidity and some bioactive compounds of rice bran

Rice bran contains natural phytochemicals but unstable against hydrolytic and oxidative rancidity. Various heat treatments, such as dry-heating (DH), freeze-drying followed by dry-heating (FDDH), microwave heating (MH), autoclaving (AC), and ethanol vapor (EV) treatment were applied to rice bran and their effects on the storage stability at room temperature were evaluated. The free fatty acid (FFA) content of untreated rice bran gradually increased from 2.14 to 19.81% during 24 weeks, whereas those of the treated rice brans were not or marginally changed. The FFA content in DH samples was greater than that in FDDH samples, indicating the positive effect of freeze-drying prior to DH. Among the treatments, autoclaving was most effective in retarding the FFA formation. The tocol content in the rice brans varied with the treatments, ranging from 181.4 mg/kg (EV) to 310.6 mg/kg (AC), whereas that in untreated rice bran was 216.3 mg/kg. Amounts of other bio-functional components such as phytosterols and policosanols were either unchanged or increased by the treatments. Policosanol level was increased by all the heat treatments, but not affected by EV treatment, indicating that the thermal treatments induced the release of free policosanols.